I would like to make a complete transformation of one of our pipelines. In a way, to redo our deals to another structure etc. For now, each deal represented company - but that is not effective, so I will be splitting it into more smaller deals etc. 

Ideally I would like to test it first, how it will work - but ideally with our real data. I want to to as if you would recommend me to duplicate current pipeline and build it there or test in in Sandbox - but not sure if I can import there some real data. What do you think? How you do the transformation?